One of the founding members of The Byrds
, and, along with Roger McGuinn
and David Crosby
, one of only three suriving members of the orginal five Byrds.
Originally started in bluegrass, so his abilities on the mandolin served The Byrds well in some of their folkier tunes.
This also positioned him well when Gram Parsons joined the band for a very brief period and took them toward a more country sound with "Sweethearts of the Rodeo," a landmark album in the history of rock.
He left the group and joined with Parsons in The Flying Burrito Brothers, and has belonged to several other groups, including various recombinations of Byrds' members such as "McGuinn, Clark, Hillman" (including original Byrd Gene Clark).
Has put out numerous solo albums and in the mid-90s belonged to the band Desert Rose, which had some popularity among mainstream country audiences.
I hear he lives in Santa Barbara, Calif., and is a convert to Greek Orthodox Christianity, thanks to his wife, who is of Greek heritage.